Blade drawing die



Oct. 8, 1935. l .1.H. L. DE BATS BLADE DRAWING DIE Filed July 1'7, 1933 ATTORNEYS.

Patented Oct. 8, A 1935 STATES UN l T.

BLE DRAG DEE lean Hubert Louis lllie lliats, East Grange, N., l?.

Application July 17, i933, Serial No. 680,62@

Claims.

This invention relates to improvements in safety razor blades and other blades having one or more cutting edges and alsoV to a novel method and apparatus for forming cutting edges on strip d steel and without the intervention of grinding operations. v

More specifically the invention contemplates the formation oi cutting edges on blades such as safety razor blades by drawing the blade strip or l0 skelp through diamond or like drawing and forming dies whereby the metal is compacted and densied at the edge portion while simultaneously having imparted thereto cutting edges.

l-Iitherto in the formation of safety razor blades the edges have been produced by a plurality of grinding and honing operations. In these operations a continuous strip is fed through a machine and transversely disposed grinding wheels remove the metal of the edge to give it a desired shape. However, the particles of abrasive in the grinding wheel gouge out the metal of the cutting edge so that the ilnished, ground edge has substantially a wavy or corrugatedappearance and the temper of the metal is partially drawn through the friction of the grinding wheel. This-condition is not remedied, to any great extent, by the subsequent honing operations because of the fact that the gouges or grooves are too deep-seated. When such blades are placed on the market they give substantially no ysatisfaction because of the soft, wavy condition of the cutting edge.

It is a feature of this invention to provide an improved, unground cutting edge for bladed articles having keen hard-cutting edges, such as safety razor blades. Another feature of this invention is the provision of a densiiled, unground cutting edge ior blades such as safety razor blades. A further feature of this invention is the provision of a drawn and densied, cutting edge for safety razor and other blades, which edge is unground. v

Other novel features of the present invention include the provision of an improved method and unitary apparatus for drawing finished densified cutting edges on safety razor blades.

These and other desirable features and advantages of the present invention will be described with reference to the accompanying drawing, in which a preferred form of apparatus is shown by way of illustration only, and in which examples of the improved razor blades of the present invention are shown, it being understood that the 'examples here disclosed are given by way of i1- lustratiomonly, and it is not intended to be limited to the examples here shown unless such limitations are clearly imposed by the appended claims.

In the` drawing like numerals refer to similar parts throughout the views,` of which (Cl. MD5-26) Fig. l is a top plan view of a machine adapt-l ed for use in imparting drawn cutting edges to safety razor blades;

Fig. 2 is a vertical plan view taken on line 2-2 of Figs. l and d;

Fig. 3 is a horizontal view of the throat machine taken on line 3--3 of Fig. 2;

Fig. l is a vertical section through the machine taken'on line l-ilof Fig. i;

Fig. 5 is a cross-section of a blade strip showing the preliminary drawing of cutting edges;

Fig. 6 is a view similar to Fig. 5 showing the drawing process substantially completed; and

Figs. 7 and 8 are enlarged sections o a finished blade showing a densiiication of the metal of the cutting edges.

Referring now to the drawing, the improved apparatus comprises a drawing mill of generally box-like shape having top and bottom plates lll and ll of suitable thickness and materiahpreferably steel plate. In addition the machine has supporting side walls iii, is and apertured front and back walls ld, l5. The walls iii and i5 are apertured, as indicated at it and il, to provide a passage or throat through which the slrelp or sheet strip i@ is drawn. The various wall portions are held together in a suitable manner, as by means of machine screws ld. A pluralityof opposed draw plates til and di are mounted vertically within the machine. rlhese plates are spaced and held laterally by means of idler rollers d@ adapted for free rotation upon shafts ril, which are mounted in bearing blocks fit. These blocks may be provided with opposed recesses it adapted to receive tension springs itil. These springs tend to lreep the idler roller assemblies spaced apart. The shafts @il are threaded, at one end as indicated at li, to receive Spanner nuts fili by means of which the draw plates Sil, 3i are held in position laterally in the apparatus. A 40 suitable number of draw plates may be mounted in the machine, idler rollers being of sufficient width to insure the desired spacing between the iinished cutting edges. lihese rollers @il will, therefore, normally approximate the width of the body portion of the ordinary safety razor blade. The draw plates may be adjusted by means of screws t@ and associated locking nuts 5i. By varying these members the aperture distance ben tween the diamonds or drawing sections 32 of the drawing plates can be varied as desired. The diamonds or refractory compositions 32 may be mounted in the plates 30 and 3l in the usual manner. Adjusting screws 52 may be provided in of the the front of the machine to control or prevent 5 5 any up-and-down movement of the drawing plates 3i) and 3 l.

The razor blade strip or skelp 2d is passed through the machine, preferably being drawn therethrough, as by means of a Steckel mill drive 60 yus or the like, in which the material is pulled through the rollers and is not driven by the rollers. The diamonds, or other likemembers 22 in the draw plates, are spaced apart a sufficient distance to initially score the strip at the center and edges, as indicated at BI in Fig. 5. The strip material 20 is usually in a dead soft, annealed condition. The drawing of the strip is continued or repeated a sufficient number of times until the scoring or strip-formation is completed, as indicated generally at 80a in Fig. 6. The final pass may be such as to separate the segments 2| and 22'of the original strip or skelp 20, to form a plurality of blades 23. The blades or finished blanks 23, upon microscopic examination,` will be foundsto have edge sections or sectors 24 of desired angularity and comprising densifled metal structures in which the metal is preferably more dense than the relatively flexible metal of the body of the blade. The blade blanks 23 may be punched out in any desired manner to adapt them to be fitted in the various types of safety razor blade holders. 'I'his step may be performed upon the strip sheet or skelp 20. After the blades 23 have been so treated and formed they are heattreated and drawn to impart the desired crystalline structure to the metal thereof. This heattreating step gives the desired hardness to the blade and more particularly to the cutting edges thereof, as by virtue of the more densified structure of the latter the heat-treatment provides an increased hardness over that of the body of the blade, even though the latter be initially of the same empirical composition as the material forming the edges, but with the difference, noted above, that the material of the edges has been subjected to working, as by drawing, to densify its structure as well as to provide suitably configured bladeedges.

'Ihisdifferentlal hardness of the blade edges with respect to the body of the blades, provides a desired stiffness and rigidity at the edges where it is most desired and needed, together with a desired resiliency in the center or body portion of the blade whereby the blade is adapted to be conformed to the shape of the holder without flexing or buckling the cutting edges.

It will now be appreciated that there has been provided an improved safety razor blade having one or more cutting edges, which blade is characterized by densied cutting edge structures free from serrations or inequalities normally incident to blades whose cutting edges are prepared by grinding and subsequent honing. 'I'he improved blades of the present invention require no grinding to form them and the honing step may be omitted, as the drawing of these edges imparts the desired finished form and structure thereto. In addition, there has been disclosed a novel method and apparatus for directly forming such improved densified cutting edges upon safety razor blades, and other cutting members, the whole being characterized by simplicity of operation and relatively low cost, both as to initial outlay for machinery and maintenance upkeep. The drawing plates or dies may be in any suitable number and strip of any desired width may be worked up into a plurality of blade structures or strips to give finished cutting edges thereto while the strip is in an annealed state and without any grinding. This working of the strip in an annealed state permits the finishing operations such as blanking out, to be accomplished on soft metal, asvthe draw-hardened metal of the formed cutting edge is not of sulcient bulk to interpose any difilculties in the blanking-out operations. The drawn and blanked blades merely require a final heat treatment to impart 5 a desired hardness thereto, together with any finishing operations, such as honing. cleaning and/ or polishing.

While certain novel features of the invention have been shown and described and are pointed out in the annexed claims, it will be understood that various omissions, substitutions and changes in the forms and details of the devices illustrated and in its operation may be made by those skilled in the art or without departing from the spirit of the invention.

What is claimed, is:

l. An improved apparatus for drawing cutting edges on safety razor blades, comprising a supporting framework, a plurality of pairs of opposed and aligned co-acting drawing dies mounted in said framework and adapted to define a blade width between the said pairs of opposed dies, gripping means for the body portions of the blade structure between said dies, comprising idler rollers, and means for supporting` and adjusting the idler rollers and drawing dies.

2. An improved apparatus for drawing cutting edges on safety razor blades comprising, a supporting framework, a plurality of pairs of opposed 80 and aligned co-acting drawing dies mounted in the framework and adapted to define at least a blade width therebetween, rotatable gripping means for the body portion of the blade structure between said pairs of aligned co-acting dies, the said gripping means forming idler rollers and adjustable means for separately supporting and adjusting the idler rollers and drawing dies.

3. An improved apparatus for drawing cutting edges on safety razor blades comprising, a sup- 40 porting framework, drawing dies mounted in said framework and adapted to define a -blade width therebetween, the said dies including diamonds mounted in aligned relation and adapted to form grooves in metal drawn therebetween, gripping means for the body portion of the blade structure, and between said diamonds, the said gripping means comprising idler rollers, and means'for supporting and adjusting the idler rollers and drawing plates.

4. In an improved apparatus for forming razor blade edges by densifying the metal of the edges to be formed from a strip sheet, the improvements comprising opposed diamonds in strict alignment and mounted in die plates, means for adiustably supporting the die plates in position and gripping means disposed between the said die plates for engaging the body of the strip, the said gripping means comprising idler rollers mounted on common shafts and lock means on do said shafts for maintaining the said idler rollers and die plates in normal, operative position.

5. An improved drawing apparatus for safety razor blade material, comprising rollers freely mounted on supporting shafts, a supporting framework for the shafts, drawing plates mounted in the framework and between the rollers and mounted in positive alignment, said drawing plates being provided with opposed and mutually co-acting diamonds severally mounted therein, and separate adjusting means for the said roller shafts and drawing plates.

JEAN HUBERT LOUIS DE BATS. 

